Conveyor belt scrapers are used in order to remove materials from conveyer belts and clean the conveyor belt surface when its cargo has been discharged. The cargo can basically be constituted by any type of material such as for example bulk solid materials including sand or gravel. The bulk solid materials that do not discharge from the belt at the desired discharge location through the action of gravity or centrifugal force accumulates on components of the belt cleaner or the conveyor belt surface and will cause productivity, cleanliness or safety problems. Therefore, it is conventional to use two types of scrapers in order to remove the cargo from the conveyor belt, a primary and a secondary scraper. The primary scraper is used to remove the material from the conveyor belt and the secondary scraper is used to remove the stickier material from the conveyor belt.
WO12130230A1, for example, discloses a belt transfer device comprising a belt conveyor consisting of a deflecting drum and a conveyor belt for the transport of material. A connection head is associated with the belt conveyor for the further transport of the material. The conveyor belt is designed as an upper strand when seen in the conveying direction before the passage of the deflecting drum and as a lower strand. In order to scrape off material from the conveyor belt, the deflecting drum is associated with a primary scraper and the lower strand is associated with a secondary scraper, the deflecting drum and the conveyor belt being arranged in one housing and the connection head being fastened to said housing. The scraper blades of the scrapers are pressed against the conveyor belt by means of a spring in order to keep contact with the same.
A problem that arises with the above mentioned conveyor belt scraper and other available prior art is that the tension of the spring gradually will decrease during use due to the wear of the blade. Since it has been shown that the spring will drop the recommended pressure of the scraper blade against the belt surface faster than the length of the scraper blade is worn down the spring must be re-tensioned several times during the service life of the scraper blade. This procedure is a safety risk when the conveyor belts are running especially since the scrapers normally are placed in areas which are hard to reach.